Completely different geopolitical scenario. If USA exterminated Germans/Japanese then their Soviet/Communist neighbors would fill in the power/population gap.
It's also worth mentioning that the Germans and Japanese themselves were extremely brutal to their defenseless, surrendered neighbors that they attempted to colonize.
Japan's been stuck in economic collapse for 30 years and Germany's repeatedly purged its left wings.
Completely different geopolitical scenario. If USA exterminated Germans/Japanese then their Soviet/Communist neighbors would fill in the power/population gap.
It's also worth mentioning that the Germans and Japanese themselves were extremely brutal to their defenseless, surrendered neighbors that they attempted to colonize.